▎ 摘　　要

Graphene oxide (GO) was synthesized and reduced by chemical, hydrothermal and electrochemical methods. The GO and reduced GO was characterized by XRD, FTIR, absorption, Raman, FESEM and AFM methods. Chemically reduced GO (CrGO) was observed to efficiently enhance the electron transfer kinetics of varenicline compared to hydrothermally and electrochemically reduced GO. Hence, CrGO was used for the fabrication of an electrochemical sensor for the determination of varenicline in the concentration range of 0.03-50 mM with a limit of detection of 7.03 nM. The applicability of the proposed sensor was demonstrated by analyzing the biological samples containing varenicline.